Some of the things they said were good for us and some of the things we were told to avoid

Health & Science

Dogs help their owners live longer, healthier lives. A Swedish study involving more than 3.4 million participants found that people with a pooch had a lower risk of cardiovascular disease and premature death. The link was especially pronounced among people who lived alone: Those with dogs were 33 percent less likely to die early, and 11 percent less likely to suffer a heart attack. Co-author Tove Fall says dog owners are likely healthier because their pets are a “good motivation to get out and exercise.” Dogs may also strengthen the immune system; a separate study found that babies exposed to canine pets have higher levels of gut bacteria associated with a reduced risk for allergies and obesity.

Camping could help cure the grogginess and lethargy associated with poor sleep. In a University of Colorado, Boulder study, volunteers who went camping for a weekend slept almost two hours longer than normal during the trip; on their return, their melatonin levels started rising more than two and a half hours earlier than before. Researchers believe this is because increased exposure to natural light helps reverse the adverse effects that modern indoor lifestyles have on the body’s internal clock. “You hear a lot of people talk about light at night being bad,” says study author Kenneth Wright. “We think a lack of light during the day might be just as harmful.”

Chile peppers may help you live longer. In a study involving 16,000 people over about two decades, University of Vermont researchers found that those who routinely ate the hot pods were 13 percent less likely to die during that period than those who didn’t. They suspect that capsaicin, the active ingredient that gives peppers their heat, might boost metabolism and help prevent obesity, high blood pressure, inflammation, and cancer. Co-author Mustafa Chopan says eating chiles, or even just spicy food, “may become a dietary recommendation.”

Coffee does more than wake you up. Two large studies involving diverse groups of adults found that people with a daily coffee habit were less likely to die from heart disease, stroke, diabetes, or cancer. Over a study period of 16 years, people who drank two to four cups of joe a day—decaf or regular—were 18 percent less likely to die. Researchers believe the drink’s health benefits stem from its complex mixture of powerful disease-fighting antioxidants. “Drinking a couple cups of coffee a day doesn’t do you any harm,” says study author Marc Gunter, “and actually, it might be doing you some good.”

Marriage could help ward off dementia. An analysis of 15 studies involving more than 800,000 people found that those who never married had a 42 percent higher risk for this form of mental decline than those who tied the knot. Married couples tend to encourage each other to stay active, follow a healthy diet, limit alcohol consumption, and stop smoking—habits associated with a reduced risk for dementia. “Staying physically, mentally, and socially active are all important aspects of a healthy lifestyle,” says Laura Phipps of Alzheimer’s Research U.K. “These are things everyone, regardless of their marital status, can work towards.”

Breakfast could be the most important meal of the day. A study involving 4,052 healthy men and women found that those who generally didn’t eat when they got up in the morning were more likely to develop atherosclerosis, or clogged arteries. Researchers say this is likely because breakfast-skippers tend to eat more calories and unhealthy foods later in the day. “If you have a heartier breakfast,” says co-author Prakash Deedwania, “you will have healthier arteries.”

Running for a couple of hours each week could reduce the risk of early death by nearly 40 percent. After analyzing existing evidence on the link between exercise and longevity, researchers calculated that one hour of running—even at a slow pace—lengthens life expectancy by seven hours. This adds up over time; people who run regularly tend to live about three years longer than their nonrunning peers, the study found. Co-author Duck-chul Lee cautions that these gains “are not infinite”—life expectancy improvements plateau after about four hours of running a week.

Diet fads may be doing more harm than good. In a bid to clear up the confusion over what is and isn’t healthy, researchers examined 25 studies involving tens of thousands of participants. They found that many of the latest nutritional trends involve significant health risks: Coconut oil is high in artery-clogging saturated fat; juicing concentrates sugars and makes it easier to consume too many calories; and many gluten-free foods are high in processed carbohydrates, which are linked to a higher risk for type 2 diabetes. Andrew Freeman, who led the research, says the ideal diet is “mostly plant based,” predominantly consisting of “fruits, vegetables, [and] whole grains.”

Social media is making people lonely. Sites such as Facebook, Twitter, and Instagram were designed to help people connect, but a University of Pittsburgh study found that spending too much time on them could intensify feelings of isolation. When researchers surveyed 1,787 adults, ages 19 to 32, they found that those who used social media for more than two hours a day were twice as likely to report high levels of loneliness than those who did so for less than 30 minutes a day. Study leader Brian Primack describes his findings as a “cautionary tale” for social media users.

Football is even more dangerous than previously thought. A Boston University study found that 110 of 111 NFL players who donated their brains to science had chronic traumatic encephalopathy, a disease that causes the brain to waste away over time, and which has been linked to aggression, depression, memory loss, and problems with speech and vision. A separate study found that children who play youth football are twice as likely to have problems with self-control, judgment, and problem solving. “Head impacts can lead to long-term consequences,” says co-author Robert Stern. “We should be doing what we can at all levels in all sports to minimize these repeated hits.”

Tattoo ink contains dangerous contaminants that can potentially affect the body’s immune system. In a small study involving six subjects, French researchers found that those with tattoos had elevated levels of various metals—including titanium, aluminum, chromium, iron, nickel, and copper—in their skin and lymph nodes. These findings suggest that potentially harmful pigment particles go much deeper than the skin. “When someone wants to get a tattoo, they are often vary careful in choosing a parlor where they use sterile needles,” says co-author Hiram Castillo. “No one checks the chemical composition of the colors.”

Keeping secrets can lead to stress, sleep loss, and other unhealthy consequences. Researchers at Columbia University asked 2,000 people what secrets they kept and how often they thought about them. On average, participants kept 13, including five they never revealed to anyone. The more time they spent ruminating over these secrets, the less healthy they said they were. “When people were thinking about their secrets,” says lead author Michael Slepian, “they actually acted as if they were burdened by physical weight.”

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Binge-watching leads to sleep problems. American and Belgian researchers asked 423 young adults about their TV and sleeping habits. They found that those who watched back-to-back episodes of their favorite shows in one sitting had a 98 percent higher risk for poor sleep, and were more likely to suffer from fatigue and insomnia. “Bingeable TV shows have plots that keep the viewer tied to the screen,” says lead author Liese Exelmans. “We think they become intensely involved with the content, and may keep thinking about it when they want to go to sleep.”

Red meat increases the risk of death from eight major diseases. In a National Cancer Institute study of 537,000 adults between ages 50 and 71 over 16 years, researchers found that those who ate the most red meat had a 26 percent greater risk of dying from cancer, heart disease, stroke, diabetes, kidney disease, liver disease, or lung disease. They speculate that heme iron in red meats and nitrates in cured meats trigger oxidative stress, which damages cells. “Mortality is higher with higher meat intake for every major cause of death except Alzheimer’s,” says researcher John Potter.